Exploration　of　multifunctional　integrated　catalysts　is　of　great　significance　for　photocatalysis　toward　practical　application.　Herein,　a　1D　confined　nanoreactor　with　a　heterogeneous　core–shell　structure　is　designed　for　synergies　of　efficient　catalysis　and　temperature　monitoring　by　custom　encapsulation　of　Z-scheme　heterojunction　CuS　quantum　dots/BiVO4　(CuS　QDs/BiVO4)　and　Y2O2S-Er,　Yb.　The　dispersed　active　sites　created　by　the　QDs　with　high　surface　energy　improve　the　mass　transfer　efficiency,　and　the　efficient　electron　transport　channels　at　the　heterogeneous　interface　extend　the　carrier　lifetime,　which　endows　the　nanoreactor　with　excellent　catalytic　performance.　Meanwhile,　real-time　temperature　monitoring　is　realized　based　on　the　thermally　coupled　levels　2H11/2/4S3/2→4I15/2　of　Er3+　using　fluorescence　intensity　ratio,　which　enables　the　monitorable　photocatalysis.　Furthermore,　the　nanoreactor　with　a　multidimensional　structure　increases　effective　intermolecular　collisions　to　facilitate　the　catalytic　process　by　restricting　the　reaction　within　distinct　enclosed　spaces　and　circumvents　potential　unknown　interaction　effects.　The　design　of　multi-space　nanoconfined　reactors　opens　up　a　new　avenue　to　modulate　catalyst　function,　providing　a　unique　perspective　for　photocatalytic　applications　in　the　mineralization　of　organic　pollutants,　hydrogen　production,　and　nitrogen　fixation.　©　2024　Wiley-VCH　GmbH.